Male pregnancy

Don’t try this at home! Male pregnancy is an alien concept to us mammals. Yet this phenomenon is the universal reproductive mode of pipefishes, seahorses and sea dragons (family Syngnathidae, with more than 200 species). During mating, a female uses an ovipositor to transfer dozens or hundreds of her unfertilized eggs to the underside of a male, where he fertilizes them. Dad then carries his developing offspring for several weeks until they are born as tiny, independent young. The enclosed brood sacs of most syngnathid species are reminiscent of female kangaroos’ pouches, except that these fish pouches are male contraptions.